Amino substituted lower alkyl polyisobutenyl sulfides,sulfoxides and sulfones



United States Patent U.S. Cl. 260-583 3 Claims ABSTRACT OF THEDISCLOSURE A composition useful as a detergency additive in lubrieatingoils is disclosed, having the formula:

wherein R is a C -C aliphatic hydrocarbon radical, R is lower alkylsubstituted with lower alkyl amino, anisyl, or aminophenol, A is a C -Cpolyvalent aliphatic hydrocarbon radical, n is 0, 1, or 2, with theproviso that two R s can be taken together to form a C -C hydrocarbyleneradical, and m is 2 or 3.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is adivisional of application Ser. No. 461,163, filed on June 3, 1965.

This invention concerns novel sulfur derivatives which find use asdetergents in lubricating oils. More particularly, this inventionconcerns novel sulfur derivatives having one long chain hydrocarbonradical which find use as detergents in lubricating oils.

A development of major importance in the lubricating oil additive fieldhas been the introduction of ashless detergents, that is, metal freecompounds which are capable of reducing varnish and sludge deposits ininternal combustion engines. An important advantage of these ashlessdetergents is the avoidance of the ash formed by the metal saltdetergents on decomposition. Thus, valve and combustion chamberdeposition with accompanying octane requirement increase can beminimized through their use.

A variety of lower molecular weight ashless detergents have beenreported in the patent literature. See for example U.S. Patent No.3,018,251, which discloses acrylated polyamines; U.S. Patent No.2,764,551, which discloses polyesters containing amino groups; U.S.Patent No. 2,- 887,452, which discloses urethanes; and U.S. Patent No.2,371,333, which discloses esters of pentaerythritol, to mention a few.

It has now been found that sulfur-containing compounds of from about 25to 250 carbon atoms having (1) From 1 to 3 sulfur-containingfunctionalties of the formula 'S(O) wherein n is a cardinal number offrom 0 to 2, at the same end of the molecule; and

(2) An uninterrupted chain of at least 20 carbon atoms, preferably 25carbon atoms, can be used as ashless detergents in lubricating oils.Alternatively, the compounds of this invention have a long aliphatichydrocarbon chain as one part of the molecule and joined to this chainis a functionality having from 1 to 3 thioether groups bonded only tocarbon, i.e., CSC; wherein from 0 to 2 oxygens may be bonded to thesulfurs by coordinate covalent bonds.

Bonded to the short chain radical bonded to sulfur may be substituentswhich are inert (the substituents do not interfere with the preparationof the products or enhance or detract from the products utility) or doimpart desirable properties to the product. Illustrative of suchsubstituents are hydroXy, lower alkoxy, amino, lower alkyl amino anddi(lower alkyl) amino.

The molecule may be described by the following formula wherein Q is analiphatic hydrocarbon radical of from about 20 to 245 carbon atoms, A isa polyvalent (di-, trior tetra-substituted) hydrocarbon radical of from1 to 7 carbon atoms, usually an aliphatic hydrocarbon radical, Q is ahydrocarbon radical of from 1 to 8 carbon atoms, or a substitutedhydrocarbon radical of from 1 to 12 car- 0 to 2 and m is an integer offrom 1 to 3, usually of from 1 to 2.

The molecule may be further described, somewhat more narrowly, by thefollowing formula wherein R is an aliphatic hydrocarbon group, eithersaturated or having aliphatic unsaturation (e.g., olefinic unsaturation)of from about 20 to 245, usually 25 to about 150 carbon atoms, thesulfur substituent(s) being toward the end of the molecule (not morethan 6 carbon atoms from a terminal carbon atom), R is a hydrocarbylradical of from about 1 to 8 carbon atoms, more usually of from about 1to 3 carbon atoms or substituted hydrocarbyl radical of from 1 to 12carbon atoms and having from 0 to 1 atoms of Row 2 of the Periodic Tableof atomic number 7 to 8, i.e., oxygen or nitrogen (hydrocarbyl is amonovalent organic radical composed solely of carbon and hydrogen whichmay be aliphatic, alicyclic, aromatic or combinations thereof, e.g.,alkaryl or aralkyl, and may have aliphatic unsaturation, e.g.,ethylenic), n is a cardinal number of from 0 to 2, m is an integer offrom 1 to 3, usually 1 to 2; when m is 2, the two R s may be joinedtogether to form a ring with the sulfurs to which the two R s areattached together with the intervening carbon atoms. When In is two orthree, the sulfur substituents will be separated by not more than fourcarbon atoms and usually not more than two carbon atoms.

Compounds wherein m is 1 have the following formula wherein R isaliphatic hydrocarbyl of from about 25 to 150 carbon atoms, preferablyof from about 30 to carbon atoms, R is hydrocarbyl of from 1 to 8 carbonatoms, preferably hydrocarbyl of from 1 to 3 carbon atoms andparticularly preferred alkyl of from 1 to 3 carbon atoms, and n is acardinal number of from 0 to 2 or substituted hydrocarbyl as indicatedpreviously for Q, preferably substituted alkyl of from 1 to 8 carbonatoms and 1 atom of atomic number 7 to 8.

When In is 2 or 3, the compounds have the following formula wherein R isaliphatic hydrocarbyl of from about 25 to carbon atoms, more usually offrom about 30 to 75 carbon atoms, R is hydrocarbyl of from 1 to 8 carbonatoms, more usually hydrocarbyl of from 1 to 3 carbon atoms andpreferably alkyl of from 1 to 3 carbon atoms and when the two R s aretaken together, hydrocarbylene of from 1 to 8 carbon atoms, preferablyalkylene of from 1 to 3 carbon atoms, and n is a cardinal number of fromO to 2 (hydrocarbylene is a divalent radical composed solely of carbonand hydrogen and otherwise the same as the definition of hydrocarbyl)and A is a polyvalent (trior tetra-va ent) aliphatic hydrocarbon radicalwhose valences are satisfied by R and S[O].,,R and is of from 1 to 7carbon atoms, usually of from 1 to 2 carbon atoms.

3 R can also be substituted hydrocarbyl as indicated for R As alreadyindicated, two sulfur atoms will be separated by not more than fourcarbon atoms, and usually not more than two carbon atoms; preferably,two sulfur atoms are separated by from 1 to 2 carbon atoms.

As is evident from the above formulae, the compounds of this inventionare either mono-, dior tri-thioethers, sulfoxides or sulfones, wherein 1or more functionalities may be present. That is, the same molecule mayhave a sulfide and a sulfoxide or sulfone functionality, The followingformulae illustrate the various functionalities and indicate also thepreferred sub-genera.

R SR

R s B g R SIR (III) of the following formulae:

g R SCH; R s CH3 o O 1 Rs CH3 B son:

(III) wherein R R", R and R are as defined previously.

Illustrative of the various compounds of this invention are thefollowing: polyisobutenyl methyl sulfide, polyethylenyl methyl sulfide,polypropenyl methyl sulfide, poly-l-butenyl methyl sulfide,polyisobutenyl ethyl sulfide, polyisobutenyl hexyl sulfide, polypentenylcyclohexyl sulfide, polypropenyl tolyl sulfide, polyisobutenyl methylsulfoxide, polyisobutenyl phenyl sulfoxide, polypropenyl butylsulfoxide, polyisobutenyl methyl sulfone, polyisobutenyl ethyl sulfone,polyisobutenyl di(methylsulfenyl) methane, polyethenyl di(ethylsulfonyl)methane, 2-polyisobutenyldithiolan-1,3, 2-polypropenyldithiolam-1,3, 2polyisobutenyl-1,1,3,3-tetraoxodithiolan-1,3, 2- polyisobutenyl 1oxodithiolan 1,3, polyisobutenyl tris- (methylsulfonyl) methane,polypropenyl tri(ethylsulfonyl) methane, etc. (The polyalkenyl groupscan be either saturated or unsaturated having olefinic unsaturation andare from about to 150 carbon atoms.)

As already indicated, inert substituents may be present in the molecule.The substituents for the most part are hydroxyl, amino and lower alkylsubstituted with lower alkyl amino, anisyl, or aminophenol thereof.Illustrative of compositions having these substituents are polypropenylZ-hydroxyethyl sulfide, polyisobutenyl 2-ethoxyethyl sulfide,polyisobutenyl 3-isopropoxyethyl sulfoxide, polyisobutenyl Z-aminoethylsulfone, polyisobutenyl N,N-diethylaminopropyl sulfide, polyethylenylN,N-dimethylamino ethyl sulfone, polyisobutenyl p-anisyl sulfide,polypropenyl p-aminophenyl sulfone, etc.

Individual substitueuts are illustrated by amino, hydroxy,dimethylamino, pentylamino, ethoxy, propoxy, hexyloxy, etc.

The compounds of this invention can be prepared in a variety of waysaccording to known synthetic organic procedures. The sulfides can beprepared by combining the desired alkali metal sulfide with thepolyalkenyl halide, e.g., chloride or bromide. Preferably, the bromideis used since it appears to provide superior results in the engine.

The polyalkenyl halides can be obtained by polymerizing olefins fromabout 2 to 5 carbon atoms to a polymer of the desired molecular weight.Illustrative olefins are ethylene and propylene. Various methods knownin the art may be used, e.g., Lewis acid catalysts. The resultingpolymer will have residual unsaturation which can be used as the activesite for introduction of the halogen. Halogen may be introduced eitherionically or free radically.

The respective sulfoxides and sulfones can then be prepared by using avariety of oxidizing agents, hydrogen peroxide being the mostconvenient. The reaction is generally carried out in the presence of acarboxylic acid, which aids the oxidation of the sulfide to thesulfoxide or the sulfone.

The derivatives having more than one sulfur-containing functionality canbe prepared from disubstituted methanes, when the methylene group isactivated by a sulfonyl group, by preparing derivatives of a polyalkenylaldehyde, by forming the thiomercaptal, or other similar means.

The method of preparation is not critical to this invention and anyconvenient means known in the art for preparing the desired compoundsmay be used.

The following examples are offered by way of illustration and not by wayof limitation.

EXAMPLE A Preparation of polyalkenyl halides 1) Into a reaction flaskwas introduced 1,350 g. of polyisobutene (1.5 moles, approximately 900molecular weight), the mixture cooled to about -20 C. and a solution of240 g. (1.5 moles) of bromine in 750 ml. of carbon tetrachloride addedover a period of 4 hours, while maintaining the temperature below l0 C.The mixture was then allowed to warm to room temperature With stirringand the solvent removed by heating to 100 C. at a pressure of 10 mm. Hg.The residue was then analyzed for bromine. Weight percent Br=9.46,indicating an equivalent weight of 846.

(2) Into a reaction flask was introduced 1,800 g. of polyisobutene (2moles, approximately 900 molecular weight) and 1.5 liters of benzene andthe solution cooled to 0 C. Over an 8-hour period, 142 g. of chlorine(2.0 moles) was bubbled into the benzene solution while maintaining thetemperature at about 0 C. An aliquot was taken and heated to 100 C. at 5mm. Hg. to remove any volatile material and the residue analyzed. Weightpercent Cl=4.01, theory 3.9.

EXAMPLE 1 Preparation of polyisobutenyl methyl sulfide (A) Into areaction flask was introduced 162 g. (2.4 moles) of a weight percentaqueous potassium hydroxide solution and then diluted with 500 ml. ofabsolute ethanol. The solution was cooled with an ice bath, the flaskfitted with an acetone-Dry Ice condenser and then 106 g. (2.4 moles) ofmethyl mercaptan added to the solution. To the resulting potassiummethyl mercaptide was added 1,267 g. (1.2 moles, approximately 93 weightpercent of the bromide) of polyisobutenyl bromide (prepared as describedin Example A-1) in 1 liter of benzene.

The addition of the benzene solution was at a rate which maintained thetemperature below 36 C. After all of the benzene solution was added, themixture was stirred and then refluxed overnight.

The benzene phase was separated from the ethanolic phase, washed withwater until neutral and then dried over sodium sulfate. The benzene wasstripped in vacuo yielding 995 g. Analysis: Weight percent S=2.55,theoretical=3.55, percent Br=0.727.

(B) Into a reaction flask was introduced 132 g. of 85 weight percentaqueous potassim hydroxide, 400 ml. of absolute ethanol, the solutioncooled in an ice bath and 96 g. (2 moles) of methyl mercaptan added. Theresulting potassium methyl meracptide solution was then diluted with 400ml. of dioxane and 200 ml. of diethyl ether.

A benzene solution (1,172 g.) containing 80 weight percentpolyisobutenyl chloride (approximately 900 molecular weight, 4.01 weightpercent Cl) was diluted with 400 ml. of diethyl ether and the solutionadded to the above mixture. The reaction mixture was then heated toreflux for one hour, the heating stopped and the mixture allowed tostand overnight.

The reaction mixture was then repeatedly washed until neutral to pHpaper, dried over anhydrous sodium sulfate, filtered through celite andthe volatile material removed in vacuo. Yield: 841 g. Analysis: percent8:1.98 (theory, 3.37%), percent Cl=1.44, molecular weight (ThermoNAM)1022.

EXAMPLE 2 Preparation of a polyisobutenyl methyl sulfoxide (A) Into areaction flask was introduced 1,207 g. (0.925 mole) of polyisobutenylmethyl sulfide (prepared as described in Example lA) and 1 liter ofmethylene chloride, the mixture cooled at C. and a solution of 104.8 g.(0.925 mole) of percent hydrogen peroxide added over a period of 1 hour.At the end of this time, 10 ml. of glacial acetic acid was added and themixture was heated to reflux C.) and methylene chloride disstilled otf.Benzene (100 ml.) was then added to assist the removal of water, avacuum of 1 to 2 mm. Hg. being applied when the pot temperature reached100 C. The residue weighed 1,200 g. Analysis: Weight percent S=2.01,molecular weight (ThermoNAM)':l,013.

(B) Into a reaction flask was introduced 841 g. of the product ofExample 1-B, one liter of benzene, and 10 ml. of glacial acetic acid. Tothis mixture was slowly added .59 ml. of 30 Weight percent aqueoushydrogen peroxide. At the end of the addition, the mixture was heated to48 C. for a short time and then allowed to stand overnight.

After diluting the reaction mixture with one liter of ether, theethereal solution was washed with water until neutral to pH paper, driedover anhydrous sodium sulfate and then stripped of volatile materials invacuo.

Analysis: percent 5:1.80, percent Cl=1.40, molecular weight(ThermoNAM)=994.

EXAMPLE 3 Preparation of a polyisobutenyl sulfone Into a reaction flaskwas introduced 900 g. of sulfide prepared as described in Example 1(0.542 mole of sulfide, the remaining material being inert) 1.2 litersof benzene and 250 cc. of glacial acetic acid. To this mixture was added184.5 ml. of 30 weight perecnt aqueous hydrogen peroxide. At the end ofthe addition, the mixture was heated at reflux for 1 hour and allowed tostir overnight. To this mixture was then added 61.5 ml. of 30 weightpercent hydrogen peroxide and heated to reflux and held at thistemperature for 8 hours. An infrared spectrum of the product indicatedthe presence of sulforze. The reaction mixture was then washed withwater until neutral to pH paper, dried over anhydrous sodium sulfate,filtered through celite and the solvent stripped. Analysis: Weightpercent S=1.63 (theoretical=1.89%).

EXAMPLE 4 Preparation of polyisobutenyl bis(methylsulfnoyl) methane Intoa reaction flask was introduced 950 ml. of absolute ethanol and 23 g. ofsodium dissolved in the ethanol. To the sodium ethoxide solution wasthen added 172 g. of bis-di-(methylsulfonyl)methane, after which wasadded 1,000 g. of polyisobutenyl bromide (prepared as described inExample A-l) dissolved in 1.5 liters of benzene and the reaction mixturemaintained at a temperature of about 50 C. The temperature was thenraised to reflux (71 C.) and maintained for 7.5 hours. At the end ofthis time, the reaction was allowed to cool, diluted with ether andwashed with water. After drying the solution, it was filtered and thevolatile material removed in vacuo. Analysis: Weight percent S=0.71(theory=6.39).

EXAMPLE 5 Preparation of a polyisobutenyl sulfone having a hydroxylsubstituent (A) Into a reaction vessel was introduced g. (2.0 moles)sodium hydroxide and 250 ml. of absolute ethanol, followed by thedropwise addition of 2-mercaptoethanol.

To the mercaptide prepared above was added 520 g. of polyisobutenylbromide (approximate molecular weight :550) in 500 ml. of benzene andthe mixture was then heated at reflux for 18 hours. After allowing themixture to cool, the mixture was filtered and then extracted with 3aliquots of 250 ml. of water. The solution was then neutralized by theaddition of 10 ml. cone. HCl and then Washed with water until thewashings Were neutral to pH paper. After drying over anhydrous sodiumsulfate, the volatile material was removed in vacuo. Yield=442 g.Analysis: percent S=3.79, 3.75; molecular weight (ThermoNAM):467.

(B) Into a reaction flask was introduced 442 g. (0.848 mole, approximatemolecular weight 520) of polyisobutenyl 2-hydroxyethy1 sulfide, preparedas described above, 500 m1. of benzene and 20 ml. of glacial aceticacid. To this mixture was then added 287 g. (2.55 moles) of 30 percenthydrogen peroxide, the temperature rapidly rising to 60 C. After theaddition of the hydroperoxide was completed, the mixture was stirred foran additional 3 hours and then heated at reflux for an additional 2hours. The infrared spectrum of an aliquot of the reaction mixture fromwhich the solvent had been removed indicated the presence of sulfone.The reaction mixture was then diluted with 500 ml. of ether, the organicphase separated from the aqueous phase, and then the organic phasewashed with water until neutral to pH paper. A'fter drying the organicphase over anhydrous sodium sulphate, the volatile materials wereremoved in vacuo. The residue weighed 411 g. Analysis: Weight percentS=2.95%, molecular weight (ThermoNAM)=549.

EXAMPLE 6 Preparation of polyisobutenyl Z-aminoethyl sulfide (A) To 111g. (0.982 mole) of 2-aminoethanethiol hydrochloride was added 500 ml. ofabsolute ethanol and 50 ml. water, followed by the slow addition of129.4 g. (1.97 moles) of weight percent aqueous KOH while cooling thereaction mixture in an ice bath.

To the above mixture was then added 1,163 g. of polyisobutenyl bromide(82.7 weight percent active, 0.982 mole, approximately 900 molecularweight) and one liter of ether, the resulting mixture allowed to standovernight, followed by heating at reflux throughout the following day.After allowing the mixture to cool, the mixture was washed with wateruntil neutral to pH paper, dried over anhydrous sodium sulfate, filteredthrough celite and then the volatile materials stripped in vacuo.

7 Anafysis.Percent :1.41, 1.42; percent N=0.76, 0.75; percent Br=1.75;molecular weight (ThermoNAM)=l,l39

Preparation of polyisobutenyl 2-aminoethyl sulfoxide (B) To a mixture of911 g. (0.492 mole) of the sulfide prepared above, one liter of benzeneand 100 ml. of glacial acetic acid cooled in an ice bath, 55 ml. of 30weight percent aqueous hydrogen peroxide was added over a one hourperiod. After stirring for an additional two hours, the reaction mixturewas diluted with pentane, washed with water, the acetic acid extractedwith dilute base, and then repeatedly washed, adding methanol tominimize the emulsion. After distilling the benzene-water azeotrope, theresidue was diluted with pentane, extracted with ethanol, and the twophases stripped of volatiles.

Raifinate: Yield, 552 g. Analysis: percent S=0.29; percent N=0.32, 0.30.

Extract: Yield, 274 g. Analysis: percent S=l.43; percent N=0.73, 0.71.

EXAMPLE 7 Alternative method of preparation polyisobutenyl methylsulfide Methyldisulfide (113 g., 1.2 moles) in 750 m1. of methylenechloride was cooled to l0 C. while maintaining a nitrogen atmosphere,followed by the addition of 85 g. (1.2 moles) of chlorine over a twohour period. The resulting mixture was added to 630 g. (2.0 moles) ofpolyisobutene (approximately 315 molecular weight) in 500 ml. methylenechloride at 20 C. After completion of the addition, volatile materialwas stripped in vacuo at 100 C., the residue treated with Norite, anactivated charcoal, for 1 hour at 100 C. and the charcoal removed byfiltration. Yield=536 Analysis.Percent 8:353 (Theory=6.9); percentCl=3.25.

A number of other compounds were prepared according to methods describedin the previous examples. While some variations in the solvent ortemperature occurred, these were not found to significantly alfect theproducts obtained or their subsequent performance in the engine. Thehigh molecular weight olefin used was polyisobutene, either of 450molecular weight or of about 900 molecular weight. Both the chloride andbromide were used, whichever one being indicated. The sulfur analysis isreported both with the sulfide and, when applicable, the oxidized sulfurcompound. The compounds are all polyisobutenyl methyl sulfides and theirsulfoxide derivatives.

TABLE I Wt. Percent Sulfur Molecular Ex. Polyiso- Weight No. buteueHalide Sulfide Sulfoxide (ThermoNAM) 1 1. s4, 1. as

1 Polyisobutene having approximate molecular weight: A: 900; B :450

Commercial differential difluslon method for molecular weightdetermination.

3 After preparing the sulfoxide, the product was purged with nitrogen,and then heated at 100 C. for 30 minutes at 10 mm. Hg. The analysis isfor the product after the thermal treatment.

As already indicated, the compounds of this invention find use asdispersants and detergents in lubricating oils. The compounds of thisinvention find particular use in diesel engines, demonstrating excellentresults under the high temperatures at which diesel engines operate.When compounded with a lubricating oil for use in an engine, thecompounds of this invention will be present in at least about 0.1 weightpercent and usually not more than 10 weight percent, more usually in therange of about 1 to 5 weight percent.

The compounds, however, can be prepared as concentrates, due to theirexcellent compatibility with oils. As concentrates, the compounds ofthis inveniton will generally range from about 10 to weight percent,more usually from about 20 to 50 weight percent of the totalcomposition.

Usually included in the oils are other additives, such as extremepressure agents, rust inhibitors, antioxidants, oiliness agents, foaminhibitors, viscosity index improvers, pour point depressants andoccasionally other detergents. Usually, these will be present in therange from about 0.01 to 10 weight per cent, more usually from about 0.5to 5 weight percent of the composition and generally each of theadditives will be present in the range from about 0.01 to 5 weightpercent of the composition.

A preferred aspect in using the compounds of this invention inlubricating oils is to include in the oil from about 10 to 50 mm./kg. ofa zinc 0,0-dihydrocarbyl phosphorodithioate, wherein the hydrocarbylgroup are from about 4 to 30 carbon atoms. Usually, the hydrocarbylgroups will be alkyl or alkaryl groups. Other phosphorodithioates mayalso be used with advantage.

The lubricating fluids which may be used with the compounds of thisinvention (hereinafter referred to as oils) may be derived from naturalor synthetic sources. Oils generally have viscosities of from about 35to 50,000 Saybolt Universal Seconds (SUS) at 100 F. Among naturalhydrocarbonaceous oils are parafiin base, naphthenic base, asphalticbase and mixed base oils. Illustrative of synthetic oils are:hydrocarbon oils, such as polymers of various olefins, generally of from2 to 6 carbon atoms, and alkylated aromatic hydrocarbons; andnon-hydrocarbon oils, such as polyalkylene oxides, aromatic ethers,carboxylate esters, phosphate esters and silicon esters. The preferredmedia are the hydrocarbonaceous media, both natural and synthetic.

The above oils may be used individually or together, whenever miscibleor made so by the use of mutual solvents.

In order to demonstrate the excellent effectiveness of the compounds ofthis invention as detergents and dispersants in lubricating oils, thecompounds were tested in the 1-C Caterpillar Test (MIL-L-45l99conditions). The oil used was a Mid-Continent SAE 30 oil and 12 mm./kg.of zinc dialkylphenyl phosphorodithioate (the alkyl groups werepolypropylene of about 12 carbon atoms) was included.

a The weight percent is based on the total non-volatile productobtained, which generally contains about 50 to of the sulfur-containingproduct. Therefore, all the values should be reduced by from 4 to toindicate the weight percent of active material.

b The groove deposits are rated on a scale of 0 to 0 is completelyclean, while 100 is completely filled. Base oil containing the indicatedamount of phosphorodithioate is rated as 93-15-5-3.

c The land deposits are rated on a basis of 0 to 800; 0 is completelyclean and 800 is completely black. Base oil containing the indicatedamount of phosphorodithioate is rated as 500-800-370.

d The underhead deposits are rated on a scale of 0 to 10; 0 iscompletely black, while 10 is clean.

It is evident from the above table that the sulfides, sulfoxides andsulfones all provide excellent detergency under the stringent conditionsof the l-O Caterpillar Test. Of particular note is the extremely cleanunderhead obtained in most of the examples. Moreover, it is possiblethat the presence of polyisobutenyl halide is detrimental to maintainingclean pistons. By removing the undesirable halides from the compounds ofthis invention, further improvement in operating efiiciency in theengine could presumably be obtained.

I claim:

1. A composition according to the formula:

wherein R is an aliphatic hydrocarbon radical of from about 20 to 245carbon atoms, R is lower alkyl substituted with lower alkyl amino,anisyl, or aminophenyl, A is a polyvalent aliphatic hydrocarbon radicalof from 1 to 2 carbon atoms, n is a cardinal number of from to 2, withthe proviso that two R s can be taken together to form a hydrocarbyleneradical of from 1 to 8 carbon atoms, and m is an integer of from 2 to 3.

2. A composition according to claim 1, wherein R is aminoethyl.

3. Polyisobutenyl Z-aminoethyl sulfoxide, wherein said polyisobutenylgroup is of from about to carbon atoms.

References Cited UNITED STATES PATENTS 2,140,608 12/1938 Ufer 260583 XRCHARLES B. PARKER, Primary Examiner D. R. PHILLIPS, Assistant ExaminerUS Cl. X.R.

